A Type VI secretion system encoding locus is required for Bordetella bronchiseptica immunomodulation and persistence in vivo

• Published in: PloS one 2012-10, Vol.7 (10), p.e45892-e45892
• Main Authors: Weyrich, Laura S, Rolin, Olivier Y, Muse, Sarah J, Park, Jihye, Spidale, Nicholas, Kennett, Mary J, Hester, Sara E, Chen, Chun, Dudley, Edward G, Harvill, Eric T
• Format: Article
• Language: English
• Subjects: Adenosine triphosphatase; Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - physiology; Adenosinetriphosphatase; Aeromonas hydrophila; Animal models; Animals; Apoptosis; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - physiology; Bacterial Proteins - secretion; Biochemistry; Biocompatibility; Bioenergetics; Biology; Bordetella; Bordetella bronchiseptica; Bordetella bronchiseptica - genetics; Bordetella bronchiseptica - pathogenicity; Bordetella bronchiseptica - physiology; Bordetella Infections - immunology; Causes of; Cytotoxicity; Domestic animals; E coli; Escherichia coli; Food science; Genes; Immunologic factors; Immunomodulation; Infection; Infections; Interleukin 1; Interleukin 10; Interleukin 17; Interleukin 6; Interleukin-17 - biosynthesis; Interleukin-1beta - biosynthesis; Interleukin-6 - biosynthesis; Laboratory animals; Loci; Macrophages; Macrophages - immunology; Mice; Molecular biology; Multigene Family - physiology; Nose; Pathogenesis; Pathogens; Physiological aspects; Physiology; Proteins; Respiratory tract; Salmonella; Salmonella Typhimurium; Toxicity; Tropical diseases; Up-Regulation; Vibrio cholerae; Virulence; Virulence Factors - genetics; Whooping cough
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0045892

Type VI Secretion Systems (T6SSs) have been identified in numerous gram-negative pathogens, but the lack of a natural host infection model has limited analysis of T6SS contributions to infection and pathogenesis. Here, we describe disruption of a gene within locus encoding a putative T6SS in Bordetella bronchiseptica strain RB50, a respiratory pathogen that circulates in a broad range of mammals, including humans, domestic animals, and mice. The 26 gene locus encoding the B. bronchiseptica T6SS contains apparent orthologs to all known core genes and possesses thirteen novel genes. By generating an in frame deletion of clpV, which encodes a putative ATPase required for some T6SS-dependent protein secretion, we observe that ClpV contributes to in vitro macrophage cytotoxicity while inducing several eukaryotic proteins associated with apoptosis. Additionally, ClpV is required for induction of IL-1β, IL-6, IL-17, and IL-10 production in J774 macrophages infected with RB50. During infections in wild type mice, we determined that ClpV contributes to altered cytokine production, increased pathology, delayed lower respiratory tract clearance, and long term nasal cavity persistence. Together, these results reveal a natural host infection system in which to interrogate T6SS contributions to immunomodulation and pathogenesis.